Catalytic naphtha reforming is an important industrial process. During the naphtha reforming process, mainly low-octane straight chain alkanes (paraffins), with 6-10 carbon atoms, are reformed into molecules having straight chain alkanes, branched alkanes (isoparaffins) and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons such as benzene, toluene and xylenes (BTX) in the reformate. The naphtha feedstock used for catalytic reforming contains naphthenic hydrocarbons, paraffinic hydrocarbons and aromatic hydrocarbons of different carbon numbers. The major reactions in naphtha reforming process include dehydrogenation of naphthenes, dehydrocyclization of paraffins, isomerization of paraffins and hydrocracking. The chemical reactions in reforming process occur in presence of a catalyst and a high partial pressure of hydrogen. The catalysts used for reforming process are usually bifunctional in nature (i.e. having metal function and the acidic function). In a typical reforming process, naphtha is processed over the conventional acidic reforming catalysts where, one or more dehydrogenation metals, i.e. noble metals with stabilizing metal ions are supported on chlorided Al2O3. These conventional reforming catalysts comprises platinum alone or along with Re, Ir, Sn or Ge as a promoter metals on gamma alumina support. However, it is observed that reforming of naphtha in the presence of conventional catalysts results in undesired gaseous products.
Further, the gamma alumina support of the conventional reforming catalysts consists of corrosive and non-eco-friendly ingredients such as chloride that provides required acidity essential for the process. However, the activity of the conventional catalysts decreases due to the formation and accumulation of coke on the catalyst surface and sintering of metals on the catalyst surface during the reforming process.
In the conventional reforming process, the C8 aromatic isomers formed i.e., ethyl benzene (EB), para-xylenes (p-X), meta-xylenes (m-X), and ortho-xylenes (o-X) appear in thermodynamic equilibrium in the product. Generally, the ethyl benzene formed during the conventional reforming takes an idle ride in the post reforming downstream p-xylene recovery unit, thus occupying unit capacity and leading to undesired operating cost.
Therefore, there is a need of a catalyst which reduces the formation of ethylbenzene in the product. Further, there is a need of a catalyst that overcomes the drawbacks associated with the conventional catalyst.